A Sumter Utilities vehicle contracted by S.C. Electric & Gas plunged from an overpass in downtown Charleston near Morrison Drive and Huger Street around 3 p.m., authorities said.

Charleston Police Department spokesman Charles Francis said a boom atop the utility truck caught a sign, causing the truck to tumble over the wall and to the grass below. The truck apparently was northbound on U.S. Highway 17 at the time.

Two men were trapped in the truck, officials said, and were later rescued.

Both men are in serious condition, according to Charleston County rescue officials. But Francis said their injuries were not life-threatening.

Officials did not immediately say which sign the truck hit. But the only sign in the area is a yellow and green one indicating the exit-only lane toward Meeting Street.

SCE&G confirmed through their official Twitter page that a contract crew was involved in the accident.

The incident was not related to work being done on the bridge earlier in the day when a rope fell onto traffic at around 11:10 this morning, according to Kim Asbill, an SCE&G spokeswoman.

SCE&G crews had been pulling the heavy rope across the bridge when the brake mechanism on the rope-pulling machine failed, according to utility officials. Three street light poles on the bridge were broken when the rope snapped.

SCE&G officials had said that crews would remain on the scene today to secure the area and repair the broken street light poles.

Check back with postandcourier.com for more information as it becomes available.